Find the value that makes these ratios equal

50:150, 75:?

The ratios can also be written 50/150 = 75/x

Now you are simply dealing with 2 equivalent fractions

50 x 1.5 = 75
so multiply the 150 by 1.5
150 x 1.5 = 225

50:150 = 75:225

The other way you could have done it is look at how you get from 50 to 150, then do the same thing with the 75
So 50 x 3 = 150
75 x 3 = 225

Put them as Fractions and simplify

50/150 = 1/3
75/? = 1/3

75/? = 1/3
75 = 1/3 ? Multiply ? on both sides
225 = ? Multiply 3 on both sides, doing so puts ? by itself.

50:150
75: 225